System of control



March 1, 1927. 1,619,398

E. M. BouToN SYSTEM OF CONTROL Filed Oct. .7. 1921 WITNESSES: INVENTOR dydr/Vl 5001011 ATTORNEY PM! Mai- 1,1921

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. Application filed October 7, 1921. Serial No. 505,982.

My'invention relates to systems of control and it has particular relation to systems emplo ed in connection with'elevators, hoists and the like.

An object of my invention is to provide means for controlling the operating speed of alternating-current elevator motors which are sub'ect to widevariation inloads."

Anot er object of my inventionis'to provide means for efiecting accurate stops or landing with an elevator c'ar,regardless of the skill of the operator.

Other objects of my invention will be systems commonly employ two-speed motors of special design, having high and low-speed operating windings. Such systems are satisfactory in general but the motors are .larger and .more expensive than standard -single speed motors and are less flexible in operation than is the system which I pronating-current motor with a system of control-similar to that employed in connection with two-speed motors. The motor is connected, for normal operation, to a source of supply of constant or normal frequency.

F or low-speed operation, the motor receives current at a reducedirequenc from a rotary-converter or frequencyr anger. The

rotary-converter is of. "a selfstarting type such as that described in United States Patent No. 1,235,583 to FriedrichW. Meyer and assigned to the Westinghouse Electric & Manufacturing Company. The motor is directly under control of the elevator operator by means of the usual car switch. To eliminate the necessity of em loying skilled operators, automatic control ing means is provided comprising a switching mecha- I propose to employ a single-speed alter-' nism, which, for convenience, is mounted on the car andis actuated by cams in the hatcliway. When the operator returns the car switch to its off position, for efiectin a stop approximately level withthe desire landing, he. actuates a switch which continues the movement of the elevator car effect an accurate landing.

Door switches,- commonly employed for another purpose, may be utilized to accomplish the operation described, or a manually operated switch or push button may, in some instances, be more desirable. In the copendin application of H. D- J ames, Serial 0. 435,777, filed January 8, 1921,

which has matured into Patent No. 1,448,407,

assigned to the Westinghouse Electric & Manufacturing -Company, the details of such arrangement are described and they constitute no art of my invention.

The single gure of the ,drawing is a diagrammatic representation of circuits and apparatus embodying my invention.

A hoisting motor 1 is connected through reversing contactors 2 and 3, in normal oporation, to line conductors 4, 5 andfi. A frequency changer 7, which is connected to a source of energy through transformers 8 and 9, supplies energy, at low frequency, to

the motor 1 for effecting low-speed operation. Contactors 11, 12 and 13 control the secondary resistor 14 of the hoisting motor 1. Contactors 15 and 16 respectively control the high and the low-speed operations. A relay 17 controls the short-circuitin of the secondary resistor. 14 to effect acce eration of the motor. This relay constitutesthe subject-matter of the copending application of H. D. James, Serial No.-295,304, y

filed May 17, '1919, and assigned to the Westinghouse Electric & Manufacturing Company. v

A relay 18 controls resistor sections 19 which are employed in the stator circuit of the rotary converter 7. A polyphase' electromagnetic-brake 21, of well-known design, is employed for maintaining the elevator car 22 at any desired landing. A relay 23 controls the operationof the brake magnet. A relay 24 prevents the starting of thehoisting motor until the rotary-converter is operated to deliver current at suitable frequencies. Overload protection is aflord id by a relay 25. The customary auxiliary controlling devices include car switch 26, hatchway limit switches 27 and 28, door switches 29 and emergency-,switch 31. An auxiliary control switch 32, located in the car and actuated by cams 33 located in the hatcht ma be assumed that the frequency changer is in operation and that the sev- 0 eral switches and controlling devices occupy their respective illustrated positions.

The oper-ating coil of the relay 37 is normally energized by a circuit extending from line conductor 4through conductor 34, op-

crating coil '46 of relay 37, door switches 29, conductor 47, switch 31, limit switches 28 and 27 and conductor 61 to line conductor 6.

Therelay 24 is normally closed, since its coil 48 is energized from the frcquenry changer 7.

In normal operation, the elevator can moves upwardly upon the actuation of the handle'of the car switch 26 to the left, as viewed in the drawing, thereby establishing a circuit for the operating coil of the contaetor 2 extending from. line conductor 4 .through conductor 34, contact members 35 and ,36 of relay 37', contact members 38, 39 and-40 of the car switch, conductor 41, operating coil 42 of contaetor 2, conductors 43 and 44, relays 24 and 25, conductor 45, switch 31, limit switches 28 and 27 and conductor 61 to line conductor 6. The contactor 2 closes to partially complete the primary circuits of the motor '1 for operation in the up direction.

In normal operation, the car switch is actuated to the extreme left, causing a relay 49, which may be termed the transfer relay, to establish a circuit for the operating coil of the high-speed contaetor 15. The circuit for the operating coil of the transfer relay 49 extends from line conductor 4 through conductor 34, contact members 35 and 36, contact members 38, 39 and 51, of therar-switch conductors 52 and 53, coil ,54, conductors 55 and 44 and relays 24 and- 25 to line conductor 6-, as previously traced.

The circuit for the operating coil of con- 4 5o taetor 15 extends fromv line conductor 6 through conductor 61, switches 27, 28'-and 31, relays 25 and 24, conductors 44 and 43,

contact members 58 and 59 of the. transoperating coil .56 of contaetor 15, conductor 5 55 fer relay 49 and conductor 34 to lineconductor 4. T I

Upon the closing of contaetor 15, current is supplied to the primary windings of themotor 1 as follows: from the conductor 6 through conductor 61, contaetor 2, conducthr'ough primary windings of the (1 conductor 68, contaetor 2, conductor conductor4. The primary windings are alsoresistor 14 is connected, in the usual manner, I

to the slip rings 74, 7-5 and 76 of. the motor 1 and is excluded from the secondary circuit by the successive closure of accelerating contactors 11, 12 and 13. The calibrating coil 77 of the accelerating relay 17 is connected across sections of the resistor 14 and is, therefore, subject to the value of the current traversing the secondary resistor, as measured by the drop in potential between the} points of connection.

The holding coil 78 of the relay 17 eflects the release of the relay contact fingers which are subse uently controlled by the calibrating coil 7. The holding-coil circuit extends from line conductor 6 through conductor 61, interlock 62 attached to contaetor 2, conductor 63, coil 78, conductor 79, interlock 81 attached to contaetor 15, conductor 52, contact members 51, 39 and 38, contact members 36 and 35, and conductor 34 to line conductor 4. Subject to the gradual drop in potential applied to calibrating coil 77, contact fingers 82, 83 and 84 successively engage contact members 85. The 'operatlng coils 86, 87 and 88 of accelerating contactors 11,

12 and 13, respectively, are successively energized by the engagement of contact members 82, 83. and 84 with contact members 85.

The contact members 85 are connected to line conductor 6 through conductor 63 and interlock 62 of the contaetor 2. A circuit extends from contact finger 82 through coil 86 of contaetor 11, conductor 79, interlock I 81, conductor 52 and through the ear-switch to line conductor 4. Coil 87 of contaetor 12 and coil 88-of contaetor 13 are connected to- Circuits through coils 87 and 88 are com pleted through contact members 83, 84 and 85 to line conductor 6. The motor now 0 er-' ates at maximum speed, with the secon ary resistor 14 short-eircuited.

Contactor 91 isnormall'y closed to connect the primary transformer windings 8 a'nd 9 in circuit with the frequency changer 7 A,

circuit for the actuating coil of the contaetor 91 extends from line conductor 4 through opera-ting'coil 92, conductor45, switch 31, limit switches 28 and 27, and conductor 61 to line conductor 6. The frequency changer contacts 51,39 and 38, as previously traced,

, with its stator winding.

7 is now operating ata reduced speedbecause of resistors 19' which are in circuit The value of the resistors 19 is such as to provide current at 'a suitably reduced frequcnc so that the hoisting motormay be trans erred from its high speed to its low-speed connections without producing an excessively sudden reduction in the motor speed.

To effect this change, the car switch 26 is moved towards its off position to disengage the contact member 51 from contact member 39. The operating coil 54 of the 27 and' conductor 61 to'line conductor 6.

The-opening of high-speed conLactOr interrupts' the circuit for coil 78 of the accelcrating relay 17 through interlock 81. The contact fingers 82, 83 and 84 are returned to their inoperative positions to effeet the opening ofcont'actors'll, 12 and to'- the frequenc 13 and to reinsert starting resistor 14. The

contactor 16 closes immediately after the opening of contactor 15 to'establislr lowspeed connections for. the hoisting motor 1 changer 7. This circuit may be traced rom conductor 96 through conductor 61, contactor 2,, conductor 65,

through one phase of the primary winding of the motor .1 to conductor 66, coil 67, conductor 68, contactor 2, conductor 69 and.

. contactor 16 to conductor 97. A motor terminal is also connected through conductor 71,"coil 72, conductor 73 and contactor 16 to conductor 98. .The contactor 18 is closed to exclude a portion of the resistor sections a -19, fromthe stator circuit of the rotary-converter to effect-an increase in the speed of the. latter and a reduction in the frequency of the current delivered to the hoisting motor. The circuit for the operating coil of the contactor 18 extends from line .con-

ductor 6,. through coil 99, contact members 93 and 59 of the t-ransefer relay 49 andconductor 34 to line conductor 4.

I The closure of contactor 16 completes a. circuit for energizing holding coil 78 of the accelerating relay '17. This circuit extends from line conductor 4 through conductor" 34, contact members 59 and 93, conductor is employed, together with a rotary-converter -95, interlock'10'1, conductor 79, coil 78, conductor 63, interlock 62 and conductor 61 to line "conductor 6. Contact fingers" 82, 83 and 84 of the accelerating relay 17 again operate to short-circuit reslstor. 14, as the ele* vator speed is gradually .reduced to a minimum. Resistor 14 limits the motor current during the slow-down period and thereby prevgnts too rapid change in torque and s cc While the elevator is below the desired landing, and moving u ward, the cam 33 is out of engagement wit the switch 32, and the spring 103 causes theengagement of contact members 32 and 104. A circuit exists, therefore, to maintain the contactor 2 closed after the car switch is in its off position; This circuit extends from line conductor 4 through conductor 34, contact members 35, 102, 32 and 104, conductor 41, coil 42 of contactor' 2, conductors 43 and 44 andrelays 24 and to line conductor 6, as previously traced.

Assuming that the elevator is about to stop at the desired landing, after the o erator has released the master switch 26, e will actuate one of the door switches 29, interrupting the circuit through the coil 46 of the relay 37, thereby efi'ecting engagement of contact members and 102.

The car continues to move upward at a very slow speed until thecam 33 actuates the switch 32 to its inoperative position when the elevator is substantially level with the desiredilanding.

- The separation of contact members 32 and 104 opens the. circuit of actuating coil 46 of contactor 2, and the latter opens the circuit of the motor 1. The opening of interlock 62 connected to contactor 2 effects the de-energization and application of brake 21.

If, for an reason, the car should travel beyond the esired landing, its motion will be reversed upon the operation of the cam to effect the engagement of contact members 32 and 105 to effect the closing of reversing contactor 3. The car' is brou ht to rest upon its becoming level with the ending by reason of the switch 32 being actuated to its central or inoperative position to eflect the opening of the motor circuits in a manner corresponding to that previously described.

The operation of the "elevator-downward isefiected in substantially the same manner as is'its upward-movement, which will be readily understood by those familiar with the art. It is therefore considered unnecessary to trace the circuits which are com "pleted by the actuation of the car switch in effecting the closure of the reversing con? tactor 3 and in repeating the functionmg of the control system, previously described I have described an elevator system in which a standard single-speedhoisting motor of small capacity relative to that of the hoisting motor. i It will be recognized that, in practice, therotary-converter is carrying load for a much shorter period, in the cycle of operation of=the elevator, than is required of the elevator motor.

WVith my system, it is possible to obtain very low operating speeds which are recognized as desirable for effecting accurate landings. It has been found desirable to automatically control the speed of the retary-cmverter, as well as the secondary current of the hoisting motor, to insure smoothness of operation when transferring from high to low operating speeds. With the system which I have described, it will be found practical to operate alternating-current elevators at a much higher speed than has heretofore been advisable.

-I claim as my invention 1. The combination with an elevator car and an alternating-eurrent hoisting motor therefor, of means for supplying energy at different frequencies, means for selectively varying the frequency applied to said motor, and electroresponsive means for insuring gradual change in the value of frequency I to insure an accurate and smooth stop of the elevator car. I

2. The comb1nat1on.w1th, an alternating current motor, of a supply source of constant frequency, means for converting the frequency, a switch for connecting the motor selectively to the source of supply or to the converting means, manually operable means for initiating said change in motor connectionsand for varying the frequency of said converting means, and frequency controlled means-for controlling the initial motor connections.

3. The combination with an elevator and an alternating-current hoisting motor, of a source of energy .at constant and variable frequencies therefor, for operation of said motor at different speeds, a switch actuated by the elevator operator for effecting lowspeed motor connections to further vary the value of the frequency, and means responsive to the frequency of said variable source for controllin said motor.

4. The com ination with an elevator and an alternating-current hoisting motor, of a supply source of constant frequency, therefor, means for converting the frequency to,

trolling means for said motor, a switch and electroresponsive means controlled in ac- -ly simultaneously with the motor connecling the frequency, for effecting the actuation of the car substantially to a floor level and for rendering said controlling means inoperative when said door switch is open.

T. The combination with an alternating-cin'rent motor and a source of energy therefor, of controlling means, a frequency converter for effecting slow operating speed of the motor and means controlled in accordance with the value of the current and frequency supplied by said converter for controlling said motor.

8. The combination with an elevator car and a hoisting motor therefor, a supply source of normal frequency, electroresponsive means for reducing the frequency supplied to the motor, controlling means for selectively connecting the motor to operate on either normal or on reduced frequency, and current limiting means for controlling the secondary current of said motor and the value of the applied frequency substantialtions.

9. The combination with an elevator car and a hoisting motor therefor, a supply source .of normal frequency, means for re-' ducing the frequency supplied to the motor, controlling means for said motor comprising a car switch for selectively connectin the motor to operate on either norma or on reduced frequency, current limiting means for controlling the secondary current of said-motor and the value ofthe applied frequency substantially simnlta' ously with the motor connections,

switch for. efiecting the actuation "of the 'c arl substantially to a floor level independently of the cars'witch.

10. The .{combination with an elevator car and ver ter controlled in accordance with the position of the switch for effecting slow operating speed of the motor independently of the controlling means, and means for preventing operationof said motor until the frequency supplied by the converter is of a predetermined value.

11. The combination with an elevator car,

an alternating-current electric motor operatively connected thereto and means for supplying energy at different frequencies-tovsaid motor, of a rheostatio controlling -.device for selectively determining and gradually position and said car is not level with an 10 adjacent landing and for automatically interrupting the circults of the motor when the car is substantially level with a landing. T

In testimony whereof, I have hereunto subscribed my name this first day of Octo- 15 her 1921.

EDGAR M. BOUTON. 

